<template>
  <div class="article-container">
    <!-- 导航栏 -->
    <van-nav-bar
      class="page-nav-bar"
      left-arrow
      @click-left="$router.back()"
      title="黑马头条"
    ></van-nav-bar>
    <!-- /导航栏 -->

    <!-- 内容区域 -->
    <div class="main-wrap">
      <!-- 加载中 -->
      <div v-if="loading" class="loading-wrap">
        <van-loading color="#3296fa" vertical>加载中</van-loading>
      </div>
      <!-- /加载中 -->

      <!-- 加载完成-文章详情 -->
      <div v-else-if="article.title" class="article-detail">
        <!-- 文章标题 -->
        <h1 class="article-title">{{ article.title }}</h1>
        <!-- /文章标题 -->

        <!-- 用户信息 -->
        <van-cell class="user-info" center :border="false">
          <van-image
            class="avatar"
            slot="icon"
            round
            fit="cover"
            :src="article.aut_photo"
          />
          <div slot="title" class="user-name">{{ article.aut_name }}</div>
          <div slot="label" class="publish-date">
            {{ article.pubdate | relativeTime }}
          </div>

          <!-- 关注模板 -->
          <follow-user
            class="follow-btn"
            v-model="article.is_followed"
            :user-id="article.aut_id"
          />
        </van-cell>
        <!-- /用户信息 -->

        <!-- 文章内容 -->
        <div
          class="article-content markdown-body"
          v-html="article.content"
          ref="article-content"
        ></div>
        <van-divider>正文结束</van-divider>

        <!-- 底部区域 -->
        <div class="article-bottom">
          <van-button class="comment-btn" type="default" round size="small"
            >写评论
          </van-button>
          <van-icon class="comment-icon" name="comment-o" info="123" />

          <!-- 收藏文章的模板 -->
          <collect-article
            class="btn-item"
            v-model="article.is_collected"
            :article-id="article.art_id"
          ></collect-article>

          <!-- 文章点赞的模板 -->
          <like-article
            class="btn-item"
            v-model="article.attitude"
            :article-id="article.art_id"
          ></like-article>
          <van-icon name="share" color="#777777"></van-icon>
        </div>
        <!-- /底部区域 -->
      </div>
      <!-- /加载完成-文章详情 -->

      <!-- 加载失败：404 -->
      <div v-else-if="errstatus === 404" class="error-wrap">
        <van-icon name="failure" />
        <p class="text">该资源不存在或已删除！</p>
      </div>
      <!-- /加载失败：404 -->

      <!-- 加载失败：其它未知错误（例如网络原因或服务端异常） -->
      <div v-else class="error-wrap">
        <van-icon name="failure" />
        <p class="text">内容加载失败！</p>
        <van-button class="retry-btn" @click="loadArticle">点击重试</van-button>
      </div>
      <!-- /加载失败：其它未知错误（例如网络原因或服务端异常） -->
    </div>
    <!-- 内容区域 -->
  </div>
</template>

<script>
// 加载文章详情请求的方法
import { getArticleById } from '@/api/article'
// 加载图片预览组件
import { ImagePreview } from 'vant'
// 加载关注组件
import FollowUser from '@/components/follow-user'
// 加载文章收藏组件
import CollectArticle from '@/components/collect-article/index'
// 加载文章收藏组件
import LikeArticle from '@/components/like-article/index'

export default {
  name: 'ArticleIndex',
  components: {
    FollowUser,
    CollectArticle,
    LikeArticle
  },
  props: {
    articleId: {
      type: [Number, String, Object],
      required: true
    }
  },
  created() {
    this.loadArticle()
  },
  data() {
    return {
      article: {}, //文章内容
      loading: true, //加载状态
      errstatus: 0, //错误状态
      followLoading: false //关注加载状态
    }
  },
  methods: {
    // 文章页面加载
    async loadArticle() {
      // 1.进入文章,执行加载状态
      this.loading = true
      try {
        // 2.加载文章详情
        const { data } = await getArticleById(this.articleId)
        // 3.渲染文章内容
        this.article = data.data

        // 初始化图片预览
        setTimeout(() => {
          this.PreviewImage()
        }, 0)
      } catch (err) {
        // 4.加载失败,判断加载状态,并添加状态
        if (err.response && err.response.status === 404) {
          err.status = 404
        }
      }
      // 5.成功与否,关闭loading
      this.loading = false
    },
    // 图片信息获取
    PreviewImage() {
      // 获取图片节点
      const articleContent = this.$refs['article-content']
      // 获取全部图片
      const imgs = articleContent.querySelectorAll('img')
      // 获取图片链接
      const images = []
      // 遍历获取的图片
      imgs.forEach((img, index) => {
        // 接收遍历出的图片的链接
        images.push(img.src)
        // 给遍历的每一个图片片设置点击事件
        img.onclick = () => {
          // 调用图片预览函数
          ImagePreview({
            // 图片预览的内容
            images,
            // 图片预览起始
            startPosition: index
          })
        }
      })
    }
  }
}
</script>

<style scoped lang="less">
@import 'github-markdown.css';
.article-container {
  /deep/ .van-nav-bar .van-icon {
    color: #fff;
  }
  .main-wrap {
    position: fixed;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    background-color: #fff;
  }
  .article-detail {
    position: fixed;
    left: 0;
    right: 0;
    top: 92px;
    bottom: 88px;
    overflow-y: scroll;
    background-color: #fff;
    .article-title {
      font-size: 40px;
      padding: 50px 32px;
      margin: 0;
      color: #3a3a3a;
    }

    .user-info {
      padding: 0 32px;
      .avatar {
        width: 70px;
        height: 70px;
        margin-right: 17px;
      }
      .van-cell__label {
        margin-top: 0;
      }
      .user-name {
        font-size: 24px;
        color: #3a3a3a;
      }
      .publish-date {
        font-size: 23px;
        color: #b7b7b7;
      }
      .follow-btn {
        width: 170px;
        height: 58px;
      }
    }

    .article-content {
      padding: 55px 32px;
      /deep/ p {
        text-align: justify;
      }
    }
  }

  .loading-wrap {
    padding: 200px 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #fff;
  }

  .error-wrap {
    padding: 200px 32px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: #fff;
    .van-icon {
      font-size: 122px;
      color: #b4b4b4;
    }
    .text {
      font-size: 30px;
      color: #666666;
      margin: 33px 0 46px;
    }
    .retry-btn {
      width: 280px;
      height: 70px;
      line-height: 70px;
      border: 1px solid #c3c3c3;
      font-size: 30px;
      color: #666666;
    }
  }

  .article-bottom {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    justify-content: space-around;
    align-items: center;
    box-sizing: border-box;
    height: 88px;
    border-top: 1px solid #d8d8d8;
    background-color: #fff;
    .comment-btn {
      width: 282px;
      height: 46px;
      border: 2px solid #eeeeee;
      font-size: 30px;
      line-height: 46px;
      color: #a7a7a7;
    }
    /deep/ .van-icon {
      font-size: 40px;
    }
    .comment-icon {
      top: 2px;
      color: #777;
      .van-info {
        font-size: 16px;
        background-color: #e22829;
      }
    }
    .btn-item {
      border: none;
      padding: 0;
      height: 40px;
      line-height: 40px;
      color: #777777;
    }
    .collect-btn--collected {
      color: #ffa500;
    }
    .like-btn--liked {
      color: #e5645f;
    }
  }
}
</style>